Slack-adjuster.



PATENTED OCT. 8, 1907.

A. PARKER-SMITH. SLACK ADJUSTER.

APPLICATION mun JUNE 25. 190a. nnnnwnn JUNE 21, 1907.

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PATENTED OCT. 8, 1907.

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' A. PARKER-SMITH.

SLACK ADJUSTER: AFPLIOATION FILED JUNE 26, 1906. RENEWED JUNE 21, 1907.

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UNITED sTATEs PATENT, OFFICE.

AUGUSTUS PARKER-SMITH, OF NEW YORK, N. Y., ASSIGNOR TO ATLASSLAOKADJUSTER COMPANY, A CORPORATION OF NEW YORK.

SLACK-ADJUSTER.

Specification of Letters Patent.

Patented Oct. 8, 1907.

Application filed June 25, 1906, Serial No. 323,388. Renewed June 21,1907. Serial No. 380,048-

To all whom it may concern.-

Be it known that I, AUeUsTUs PARKER-SMITH, a citizen of the UnitedStates of America, and a resident of the borough of Manhattan, city,county, and State of New York, have invented certain new and useful Improvements in Slack-Adjusters, of which the following is aspecification.

My invention relates to fluid pressure brakes in gen oral, and morespecifically consists of an improved ap' paratus for automaticallytaking up the slack produced by the wearing down of the brake shoes, orotherwise, and thereby insuring a substantially uniform maximum pistontravel in the brake cylinder.

Various devices have been heretofore designed for producing this result,but they have been in many cases costly in construction, uncertain inaction, and more or less complicated. I have invented an arrangementwhich is absolutely positive and accurate in its action and is believedto contain the fewest possible number of parts.

The best form of apparatus at present known to me embodying myinvention, with some modifications, is illustrated in the accompanyingtwo sheets of drawing, in which:

Figure 1 is a section of the brake cylinder with my invention appliedthereto, the piston being in its inmost position. Fig. 2 is a detailview showing the position of the piston rod and other parts when thepiston is on its out stroke and the slack adjusting apparatus is inoperation. Fig. 3 is a similar view showing the piston rod in its inmostposition after the apparatus has operated to take up the slack. Fig, 4shows a modified arrangement of gripping device, and Fig. 5 shows aminor modification.

Throughout the drawings, like reference figures indicate like parts.

1 is an ordinary cylinder, 2 the piston, 3 the hollow piston rod commonin freight equipment, and 4 the spring which retracts the piston whenthe brake is released.

5 is the ordinary push rod, though made a little longer than is usual,and 6 one of the brake levers to which the push rod is pivoted by thepin 7.

8 is a friction dog, loosely mounted on the push rod and having a bentend 9, or other projection which engages a flange 10 on the end of thehollow piston rod. 11 is another similar dog also mounted on the pushrod 5 and having bent end 12, which engages the thimble 13 which isloose on the push rod.

14 is a stiff spring confined between the thimble 13 and the dog 8.

15 is a spring more flexible than the spring 14, which is placed on theother side of the dog 8 and confined between it and the shoulder 16formed by the enlarged end of the push rod 5.

17 is a perforated plate or other convenient form of,

combined stop for the dog 11 and support for the push rod 5, rigidlysupported with reference to the cylinder in any convenient manner, as bythe plate 18. Preferably, this stop is adjustable on the plate by meansof the bolt and slot connection 19.

The mode of operation of the construction shown in Figs. 1, 2, and 3, isas follows: The parts are so designed preferably that when new brakeshoes are in place the push rod 5 will extend throughout the wholelength of the hollow piston rod 3 with which it forms a telescopingjoint and have its inner end resting against the piston 2. The distancebetween the dog 11 and the stop 17 is the distance predetermined on asthe maximum piston travel. It is evidenbthen that for all ordinary brakeapplications, no change will take place in the relative position of theparts of the take-up apparatus, until the shoes having worn down acertain amount, and a heavy application of the brakes causes thepredetermined maximum piston travel to be exceeded. This will result inthe dog 11 being forced up against the stop 17 whose face is at rightangles to the axis of the push rod 5. This will trip the dog 11 andallow the push rod to pass through it a distance equal to the excess ofpiston travel over the predetermined maximum. This in turn will resultin compressing the spring 14 the same distance, as shown in Fig. 2. Onthe release of the brakes, when the piston 2 is forced in by the spring4, the dog 8 will be left free and the spring 14 expanding to its-normalextent will force the dog 8 to the left a distance equal to that whichthe dog 11 has been previously forced. The next time the brakeapplication is made the flange 10 will strike the projection 9 on theend of the dog 8, cause it to grip the push rod in its adjusted positionand carry the same out in its extended position, as shown in Fig. 3.Thus, every time the maximum allowable piston travel is exceeded, thepush rod 5 will be subsequently shoved out a distance equal to theexcess and held in that extended position, thereby holding the pistontravel down to the maximum or less than maximum until the furtherwearing of the shoes will cause any heavy application to produce a newadjustment. In putting in new brake shoes the dogs 8 and 11 aresimplyreleased and the push rod 5 shoved all the way in. The firstapplication of the brakes thereafter will take up the necessary amountof slack and start the series of operations before described.

Fig. 4 shows a modification designed for use on passenger cars, or othercars where it is not important to leave the push rod 5 free so that thebrakes may be conveniently applied by hand operated apparatus. In thisconstruction, the dog 8* is connected to the hollow piston rod 3 bymeans of the bent ends 20, 20. This change renders it necessary toinsure the retracting of the push rod 5 with the piston 2. This is mostconveniently done by means of the spring 21, which is compressed betweenthe shoulder 16 on the inner end I of the push rod and the inner flange10 on the hollow piston rod 3. The operation of the device so far as theaction of the two friction clutches is concerned is otherwise similar tothat previously described, with reference to Figs. 1, 2 and 3.

If desired, the thimble 13 may be replaced by the frame 22 shown in Fig.5. One corner of this frame is flattened down, as shown at 23 so as toserve as a fulcrum for the dog 11, which can then be made straight. Aspring 24 should then be employed to hold the dog 11 in engagement. Withthis form of apparatus it is not necessary that the stop 17 shouldsurround the push rod 5. Any stop which will engage the frame 22 on theoutward stroke of the piston is sufficient.

It is understood, of course, that on the release of the brakes after anapplication in which the spring 14 has been compressed as previouslydescribed, the dogs 11 and 11 will immediately grip the push rod 5again, and serve as a rigid abutment from which the spring 14 acts tothrust the dogs 8 or 8 to the left. All the dogs 11, 11, 8 and 8 are sodesigned as to slide only to the left along the push rod 5, unlesstripped by the operator.

In the construction shown in Fig. 5, the spring 24 may be made powerfulenough to clamp frame 22 and dog 11 in any position on the push rod andso prevent its jarring or jolting to the left out of any position ofadjustment under any condition short of a strong thrust such as it wouldreceive from the stop 17, and in such case the spring 15 may bedispensed with by fastening the adjacent ends of the spring 14 to theframe 22 and the dog 8 by any convenient means such as hooks 25, l 25,as shown in Fig. 5.

The advantages of my invention comprise its cheapness, but few andsimple parts being requiredyits simplicity and non-liability to get outof operative condition, and its adaptability to present constructionswithout substantial modification of standard apparatus.

It is evident, of course, that various changes could be made in thedetails of construction illustrated and described other than those shownin the modifications without departing from the principle of myinvention so long as the feature of a telescoping extensible piston rodwith means for automatically expanding the same to compensate for thewear of the brake shoes be retained.

Having, therefore, described my invention, I claim 1. In a fluidpressure brake apparatus, the combination with the usual cylinder,piston and foundation brake rigging of a telescoping piston rodconnecting the piston with one of the brake levers, and automatic meansfor length,- ening the telescoping; piston rod to compensate for thewearing down of the brake shoes, said means comprising a friction doghaving a bearing on the hollow member of the telescoping joint andgripping the other at any portion of its length. v

2. In a fluid pressure brake apparatus, the combination with the usualcylinder, piston and foundation brake rigging of a telescoping pistonrod connecting the piston with one of the brake levers, and automaticmeans for lengthening the telescoping piston rod to compensate for thewearing down of the brake shoes, said means comprising a grippingapparatus having a bearing on one member of the telescoping joint andgripping the other member at any point of its length, and mechanismwhich after the predetermined maximum of piston travel has been exceededon any stroke extends the telescopic joint after release of the brakesby an amount equal to the excess travel on such piston stroke.

3. In a fluid pressure brake apparatus, the combination with the usualcylinder, piston and foundation brake rigging of a telescoping pistonrod connecting the piston with one of the brake levers, and automaticmeans for lengthening the telescoping piston rod to compensate for thewearing down of the brake shoes, said means comprising a grippingapparatus having a bearing on one member of the telescoping joint andgripping the other member at any point of its length, and mechanismwhich after the predetermined maximum of piston travel has been exceededon any stroke extends the telescopic joint after release of the brakesby an amount equal to the excess travel on such piston stroke, saidmechanism comprising a second gripping apparatus mounted on the secondmember of the telescoping joint, a spring mounted between the two gripping devices, and an adjustable stop for the second gripping apparatus.

4. In a fluid pressure brake apparatus the combination with the usualcylinder, piston and foundation brake rigging of a hollow piston rod, :1push rod telescopcd therein and connected to one of the brake levers, afriction clutch loosely mounted on the push rod and adapted to bearagainst the end of the hollow piston, a second friction clutch alsoloosely mounted on the push rod, :1 slop therefor rigidly supported withreference to the brake cylinder. and a spring located between the twoclutches.

5. I11 a fluid pressure brake apparatus, the combination with the usualcylinder, piston and foundation brake rig ging of a hollow piston rod, apush rod telescopcd therein and connected to one of the brake levers, afriction clutch loosely mounted on the push rod and adapted to bearagainst the end of the hollow piston, a. second friction clutch alsoloosely mounted on the push rod, a stop there' for rigidly supportedwith reference to the brake cylinder, and a spring located between thetwo clutches, together with a second but more flexible spring located onthe other side of the first mentioned friction clutch and having itsouter end confined on the push rod.

(3. In a fluid pressure brake apparatus, the combination with the usualcylinder, piston and foundation brake rigging of a hollow piston rod, :1push rod having an enlarged inner end telescopcd therein and connectedto one of the brake levers, a friction clutch loosely mounted on thepush rod and adapted to bear against the end of the hollow piston, 21second friction clutch also loosely mounted on the push rod, a stoptherefor rigidly supported with reference to the brake cylinder, and aspring located between the two clutches, together with a second springconfined between the first mentioned friction clutch and the enlargedend of the push rod.

7. In a fluid pressure brake apparatus, the combination with the usualcylinder, piston and foundation brake rigging of a hollow piston rod, apush rod telescopcd therein and connected to one of the brake lovers, afriction clutch loosely mounted on the push rod and adapted to bearagainst the end of the hollow piston, a second friction clutch alsoloosely mounted on the push rod, :1 stop therefor rigidly supported withreference to the brake cylinder. and a spring located between the twoclutches, said stop also forming a guide for the push rod.

8. The combination of a hollow piston rod, :1 push rod telescopcdtherein, and the friction dog having :1 perforation through which thepush rod passes :llld a bent end which bears on the end of the hollowpiston.

D. The combination in a friction clutch of a rod, :1 per forated memberthrough which the rod passes, and :1 dog having an opening through whichthe rod also passes and a projection at one end which bears on the faceof the perforated member.

10. The combination in a friction clutch of a. rod, :1 perforated memberthrough which the rod passes, and a dog having an opening through whichthe rod also passes and :1 projection at one end which bears on the faceof the pen forated member, together with a stop located on the otherside of the dog having a bearing face in a plane at right angles to theaxis of the rod.

Signed at New'York, N. Y. this 21st day of June, 1906.

AUGUSTUS PARKER-SMITH.

Witnesses M. G. CRAWFORD, W. H. PUMPHRm'.

